One of the hardest achievements on the Xbox 360 was the original Gears of War, Seriously… achievement. You needed 10,000 kills in warzone which would take months of playing the game a steady amount of time every day. The seriously 2.0 requires 100,000 kills; however instead of in warzone alone, you can do it in every game mode, including the campaign. It would be a reasonale accomplishment after 24 hours of playing the campaign.
The achievements are all so easy. The game is only released to people who pirate the game which requires a mod chip. It’s unfair, but they’ll get their justice if they get caught by Microsoft.